We have added powerful aminopolycarboxylate chelating groups to the variable "terminal amine" region of the antitumor antibiotic bleomycin. When a resulting compound ("BLEDTA I") is mixed with short-lived, gamma-emitting radioactive metal ions such as 111In3 ion, it binds them quickly and quantitatively to yield a tumor-localizing radiopharmaceutical with biological transport properties characteristic of bleomycin. In studies with human subjects involving a variety of cancers, 111In-BLEDTA I scintillation scans agreed with biopsy results in 69 of 82 cases (84% accuracy); a positive scan predicted a positive biopsy in 67 of 68 cases (99% positive predictive value); and a positive biopsy predicted a positive scan in 67 of 79 cases (85% sensitivity). We propose to improve on the tumor-localizing properties of the bleomycin-chelate conjugate BLEDTAs by preparing analogs which, for example, do not share BLEDTAs' unusual affinity for white blood cells. For the preparation of bleomycin analogs, the general approach to synthesis of chelators from alpha-amino acids which we have recently developed will permit the preparation of "bifunctional" chelating agents with a wide choice of sidechains, electric charges, ligand configurations, and reactive groups. We also propose to develop non-perturbing procedures for noncovalently labeling cell surfaces with amphilic chelates and to investigate the use of luminescent lanthanide chelates for in vitro clinical assays. The overall objective of this project is to provide new means for the detection of human cancer by coupling metal ions with ideal physical properties to molecules with appropriate biological properties.